That's because mobile Internet providers need more room to expand their fast-growing wireless networks. Every new product, like last week's announcement of an iPhone for Verizon Wireless, ratchets up the demand for mobile data services.

With mobile networks expected to handle 35 times as much Internet traffic over the next five years as they do now, the Federal Communications Commission worries that the nation's wireless system will bog down under the strain, and has proposed a plan to repurpose spectrum now reserved for television channels.

But the broadcasters - still smarting over having to surrender spectrum two years ago for digital television - say they need those airwaves to compete with their flashy new rivals with products such as live mobile TV.

The disagreement has set the stage for a battle between the FCC and broadcasters, who have vowed to fight any government mandates that force them to move off channels they use for "Family Guy" and the evening news in order to bolster Internet connections to Droids, iPhones and Xoom tablets.

"You can't take that much spectrum from broadcasters and not have devastating consequences for delivery of mobile digital television, HDTV and other innovative services," said Dennis Wharton, vice president of the National Association of Broadcasters.

But the FCC says it is looking toward the future.

"We know of the opportunity mobile innovation represents for our economy and for job creation," FCC Chairman Julius Genachowski said in an interview. "We also know the threat is that if our invisible infrastructure isn't up to the task, it will hurt customers and innovators who will shift their focus to other markets."

In all, the FCC is proposing a voluntary auction of about 120 megahertz of additional television spectrum - but it would take at least a year for the agency to get permission from Congress and cooperation from hundreds of stations around the country. Much of that spectrum, between channels 31 and 51, isn't being used, but some broadcasters fear existing programming on those channels could be moved to less attractive swaths of airwaves.

Telecom and high-tech companies support the FCC's plan, which would be the federal government's fourth major rollout of airwaves for cellphone use. Most recently, it sold $20 billion of spectrum in 2008 for high-speed Internet networks that are just now being rolled out by Verizon Wireless and other carriers. But the demand is expected to strip even that supply.

Each mobile Internet user is expected to use four times as much data by 2015. A streaming video gobbles up about 100 times as much bandwidth as a phone call - and new technologies are coming fast.

Companies will use machines that communicate with each other for business tasks through wireless connections. Cars will be equipped with mobile Internet connections that help drivers navigate roads and feed streaming videos to headrests. Appliances will wirelessly connect to energy meters to use the least amount of energy possible.

For many smartphone customers, network congestion isn't just a problem of the future. When the iPhone debuted on AT&T in 2007, heavy demand crashed the company's system. Now millions more users are likely to sign up next month when Apple's popular bandwidth-hogging device comes out on Verizon - though that company says it is ready for the onslaught.

Many broadcasters, embattled by declining viewers, say they fail to see the benefits of surrendering spectrum for a new government auction.

Ralph Oakley is the fifth-generation leader of his family-owned Quincy Newspapers company, which runs 12 television stations in 10 Midwest markets. Even with a sweetened pot from "incentive auctions" proposed by the FCC, he has no plans to sell his spectrum.

About 10 to 15 percent of television viewers still rely on free over-the-air signals, he said. His viewers in places like Madison, Wis., range from teens to seniors who watch for weather warnings and shows on CW, NBC and Fox. This year, he plans to bring those signals to mobile devices for his local audiences.

"This is about business, sure, but what happens to the community that relies on us if we keep giving away our bandwidth?" Oakley said.

The Washington Post Co., which owns six television stations in major markets including Miami and Houston, said it generally supports the idea of voluntary auctions. "Our concern is the word 'voluntary,' because it's all in the details," said Alan Frank, chief executive of Post-Newsweek Stations. He added that the company is not looking to sell spectrum.

Many broadcasters say the government needs to first see whether any other spectrum, such as airwaves held by federal agencies, can be auctioned for commercial use.

And they note that carriers haven't built out networks from large swaths of spectrum they bought two years ago. When that is done, then come looking for more, they say.

"Why the irrational fixation on free and local broadcasting?" said Wharton, the NAB vice president.

But Gary Shapiro, president of the Consumer Electronics Association, said the broadcasters are mistaken to fight the auction.

"Broadcasters are gearing up for a huge political battle," Shapiro said, "but the reality is that fewer people are watching over-the-air television, and we're fighting for our future of innovation."